// Future

void main() {
  var delayedFuture = Future.delayed(Duration(seconds: 3), () {
    print('this is delayed future');
  });
  var commonFuture = Future(() {
    print('future is executed');
  });
  var valueFuture = Future.value(100.0);//
  valueFuture.then((value) => print(value));
  print(valueFuture is Future<double>);
}